I have been around gas cars and trucks all my life and I don't understand how are 48RE,47RE operate.

Please , in layman terms can someone explain to me this:

How do our trannys with a lock up work? in other words, when does it lock up, why in some gears and not in others. What the sam hill is a lockup???

This is my first diesel and I am thinking if I understand this tranny more maybe I can, drive, service and drive this truck smarter.

Maybe I can understand what some of you guys are saying on this site and others.

thanks in advance

 

Lockup is the TC (torque converter) clutch locking the stator on the input shaft to the TC body that is hooked to the flex plate. You have no more fluid coupling and power loss thru it. It is just like engaging a clutch in a manual setup.

The TC locks when the ECU demands it. The ECU has a set of parameters that include speed, rpm, APPS, that feed it and when they all align the ECU grounds the TC lockup wire and the converter locks.

Tow\Haul features a more aggressive lockup strategy to hellp with load moving. You want lockup sooner and more often as it puts more power to the wheels and significantly increases economy in the case of the stock TC. Of course if your racing or sled pulling the more power you put on the ground the farther and faster you go.

The TC will lock in 2nd gear, drive, and OD depending on the paramters that have been programmed into the ECU, or, you can add a lockup switch that will manually lock the TC starting in 2nd and shift locked to locked all the way to OD. After enough of that internal pieces break.

That help?

 

Yes, that helps a lot, just one question though... Do these trucks have a lockup feature because it holds the power better than none lockup Trannies?

Thanks again for the advice

 

I see you are running the DTT shift enhancer. Would you recommend it?

 

TC lock up is a fuel improvement enhancement as losses through the TC are decreased. Towing really, really heavy is bad with the TC in lock up. When the TC locks, no fluid flow occurs between the lock up clutch and the TC housing. When the lock up clutch starts to slip, it heats up decreasing the friction of the lock up clutch. Since lock up clutches in TC's are wet clucthes, the disintegrating material finds its way into the valve body and wreaks havoc.